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SPUDSMART.COM INTERNATIONAL EDITION 201526 protein that is recognized by the resistance gene in the potato. The Achilles heel theory says that if we target a protein that is essential to the pathogen then it is less likely that it will adapt she says. The approach we took is only recently possible thanks to availability of genome sequencing of phytophthora and an experimental approach effectoromics that we designed to be able to screen individual genes in a high- throughput fashion. Scientists found this essential protein in elicitin in the late 1980s initially due to work done by a research group working at the French National Institute for Agricultural Research. Many years of screening wild potatoes for elicitin resulted in its discovery in Solanum microdontum a South American wild relative of cultivated potatoes. ELR encodes a receptor-like protein in S. microdontum. Plants contain many of these cell surface receptors which act as a first line of immune defence much like an array of radar antennas. The receptors are tuned to different features of invading pathogens and in the case of this new type of blight-resistant potato the simultaneous presence of elicitin and the gene that responds to it triggers cell death at the site of infection. Its this powerful plant defense mechanism that restricts the progress of the late blight pathogen. There are two classes of immunity receptors in plants. One class functions inside the plant cell and the other on the surface of the plant cell. In the past for potato blight weve only known about the receptors that work inside the plant cell. This is the first report of a cell surface type of immune receptor against the blight Kamoun says. For resistance to be deemed durable it needs to hold over time but looking at this research the new gene is really broad-based. It is expected to offer more durable resistance in theory Bizimungu says. The knowledge were getting at the micro-level through genomics research is having a big impact on how we can combat late blight. Canadian research played a role in the discovery. Researchers in England and the Netherlands drew upon the work of Lawrence Kawchuk an AAFC research scientist based in Alberta. In 2001 he isolated one of the first plant disease receptors for verticillium wilt resistance which helps to prevent early dying in potato plants. NEW LAYER OF IMMUNITY For potato growers the late blight breakthrough is significant because it may help circumvent the pathogens major strength its ability to evolve and create new versions of itself that overcome resistance that have been bred into potatoes. I think this new layer of immunity has big potential for control of late blight on a world scale. The research is still in the experimental phase and is not strong enough yet to apply in practice. We need more research to find out how we can further enhance it and we need to find more of these genes to combine them together Vleeshouwers says. Kamoun adds that by combining different types of disease resistance we maximize our chances to delay the evolution of new races of Phytophthora infestans. According to Bizimungu the discovery holds a lot of potential for research in Canada as S. microdontum germplasm is accessible to researchers through the U.S. Department of Agriculture gene bank. He notes the elicitin resistance gene could potentially be used to conventionally breed new varieties of potatoes with stronger and long-lasting resistance to the late blight pathogen. Kamoun believes genetic modification represents the most efficient route for commercializing new blight-resistant varieties developed through elicitin resistance technique. At this stage the shortest route to deploy this resistance in the field is through a GM transgenic approach Kamoun says. It all depends on the acceptance of this technology and the willingness to invest in the cost of deregulation. The knowledge were getting at the micro-level through genomics research is having a big impact on how we can combat late blight. BENOIT BIZIMUNGU VIVIANNE VLEESHOUWERS I think this new layer of immunity has big potential for control of late blight on a world scale. The sporangia of Phytophthora infestans the pathogen responsible for late blight disease. PHOTO LAWRENCE KAWCHUK AAFC For all your packaging needs call us at 1-519-863-5782 AgricultureIndustrial Packaging Fruit and Vegetable Containers Biodegradable Shopping Bags Plastic Palletwrap Net Wrap Meshbags for CornOnionsFirewood Cardboard Boxes Waxed Paper Bags for Potatoes Wood Bushel and Baskets Plastic Trays ClumshellsPunetrays Fibre Trays 12pt and 1pt Bulk Bags Cardboard Bins NNZ Inc. Canada 135 Main Street West Norwich ON email adejongennz.ca